Method and Devices for Improved Tissue Stabilization

ABSTRACT

Devices and methods are disclosed for accessing and stabilizing an unstable or moving tissue structure within a patient&#39;s body, and in particular, for temporarily stabilizing a target site on the beating heart. The devices generally involve tissue stabilizers having at least one multiple link support member operably connecting a stabilizer foot to a retractor. The tissue stabilizer may have a stabilizer foot allowing for additional members to be connected to the stabilizer foot at discreet locations. The support member and the additional members may be attachable to a retractor. The support member and the additional members may be operably associated with attachments or mounts which provide additional degrees of freedom at a connection to the retractor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 10/637,372filed Aug. 7, 2003, pending, which is a continuation of application Ser.No. 09/452,760 filed Dec. 1, 1999 and which issued as U.S. Pat. No.6,626,830 on Sep. 30, 2003, which is a continuation-in-part ofapplication Ser. No. 09/372,661 filed Aug. 11, 1999, abandoned, which isa continuation-in-part of application Ser. No. 09/305,810 filed May 4,1999 and which issued as U.S. Pat. No. 6,331,158 on Dec. 18, 2001.Application Ser. Nos. 09/452,760, 09/372,661, 09/305,810 and U.S. Pat.Nos. 6,331,158 and 6,626,830 are all hereby incorporated herein, intheir entireties, by reference thereto.

FIELD OF THE INVENTION

The present invention relates generally to surgical instruments, andmore particularly to methods and devices for improved tissuestabilization using multiple link support members. The tissuestabilizers described herein are particularly useful for stabilizing thebeating heart during coronary artery bypass graft surgery.

BACKGROUND OF THE INVENTION

A number of surgical procedures require the surgeon to perform delicateoperations on tissues within the body that are moving or otherwiseunstable. For example, surgeons are routinely performing successfulcoronary artery bypass graft surgery (CABG) on the beating heart. In atypical coronary artery bypass graft procedure, a blocked or restrictedsection of coronary artery, which normally supplies blood to a portionof the heart, is bypassed using a source vessel or a graft vessel tore-establish blood flow to the artery downstream of the blockage. Thisprocedure requires the surgeon to create a fluid connection, oranastomosis, between the source or graft vessel and an arteriotomy orincision in the coronary artery. Anastomosing two vessels in this manneris a particularly delicate procedure requiring the precise placement oftiny sutures in the tissue surrounding the arteriotomy in the coronaryartery and in the source or graft vessel so that the two may be suturedtogether.

To ensure that the sutures may be placed with the required accuracy andprecision to yield an anastomosis having the desired long term patency,a number of devices have been developed to stabilize a portion of theheart in the vicinity of the target coronary artery. The vast majorityof devices suitable for successfully stabilizing the beating heart useeither compression or vacuum, or both, to engage and immobilize aportion of cardiac tissue, preferably along opposite sides of the targetartery. Devices configured to use a compressive force to stabilize asurgical site on the beating heart can be found, for example, in U.S.Pat. No. 5,894,843 to Benetti et al. Examples of devices configured touse negative pressure or vacuum to stabilize or to assist in stabilizingcardiac tissue are described, for example, in U.S. Pat. Nos. 5,727,569to Benetti et al. and 5,836,311 to Borst et al.

The devices used to stabilize the beating heart must be sufficientlystiff or rigid to resist or placate the movement of the still beatingheart muscle as it contracts and relaxes in regular fashion to pumpblood throughout the body. Such stabilization devices typically employ atissue engaging or contacting member and some type of support member toconnect the tissue contacting member to a stable support, such as aproperly constructed rib or sternal retractor. The support member ismost often either a continuous substantially rigid straight or curvedshaft or a multiple link member that that is sufficiently flexible forpositioning and which can be made substantially rigid for stabilization.

Multiple link members typically involve a series of in-line ball andsocket links which may be forced together axially by way of a wire orcable extending generally through the center of each link. As the linksare forced together, the frictional forces between the successive linksincrease in proportion to the axial forces supplied by the cable untilthe frictional forces within the successive ball and socket links alongthe support member become so great as to resist relative movementtherebetween, thus rendering the support member substantially rigid.Examples of articulating members having a plurality of links can befound in European Patent Application EP 0 803 228 A1 published on Oct.29, 1997 and U.S. Pat. No. 5,899,425.

While the simple operation of multiple link devices have found someacceptance as suitable support members for use in connection with tissuestabilizers, it has proved very difficult to produce the requiredrigidity and maneuverability required in certain demanding surgicalapplications, such as stabilizing the beating heart during a CABGprocedure. Regarding the rigidity of multiple link devices, for example,a great deal of axial force must be generated to ensure each of thelinks become sufficiently locked to resist any motion at the surgicalsite. To support these high loads, the links typically have a muchgreater diameter than their continuous shaft alternatives thus occupyinga greater amount of space in the surgical field.

In addition, the ability to maneuver and position the distal end of amultiple link support member as desired within the surgical field isdisadvantaged by the limited range of motion available betweensuccessive links along the support member. Attempting to position devicethrough tight turns often proves excessively difficult. For example, amulti-link device may allow each link to rotate only about 15 degreesrelative to an adjacent link. With such a configuration, articulatingthe support member through a 90 degree turn may involve six or morelinks, thus occupying an excessive amount of space in or near theoperative field and resulting in a relatively large radius curve.

Because the rigidity is somewhat inefficient, requiring an increaseddevice size and high forces, and because the maneuverability is limitedby the relatively small range of motion between adjacent links, it canbe quite difficult to reach and stabilize vessels of the beating heartwhich are remote from the access opening established by the retractor.Multiple link support members may be unable to develop the rigidityrequired for optimum stabilization of the peripheral arteries of thebeating heart and may be difficult to position at the remote locationswhich require tight turns or extreme angles of the support member or thecontacting member relative to the support member.

Further, when the proximal end of the support member is attached to theretractor in a generally horizontal orientation, it is difficult for amultiple link support member to maneuver the initial roughly 90 degreeor less turn required to position the distal end vertically down intothe target surgical site. If the multiple link support member is unableto form a sufficiently tight turn or angle relative to its attachment tothe retractor, it will tend to occupy an excessive amount of space atthe access opening thus blocking visual and instrument access to thetarget surgical site to be stabilized.

In view of the foregoing, it would be desirable to have a tissuestabilizing device having a tissue contacting member and support memberfor stabilizing the beating heart which maintains the simplicity of useinherent to multiple links systems but also provides improvedmaneuverability and rigidity for optimum stabilization. It would also bedesirable to have a multiple link support member having a proximal jointor mount which facilitates a sharp turn or angle, such as may berequired when the support member is connected proximally to a retractoror other such device.

SUMMARY OF THE INVENTION

The present invention will be described primarily for use during CABGsurgery, but the invention is not limited thereto, and is contemplatedto be useful for other surgical procedures as well.

The devices and methods of the present invention involve tissuestabilizers which are constructed to provide superior maneuverabilityand improved tissue stabilization at a target site, for example on thebeating heart. The present invention may involve stabilization devicesthat use at least one multiple link support member to operably connect astabilizer foot to a stable support, such as a retractor. To minimizemotion at the stabilizer foot and improve the overall stabilization of atarget site, the present invention may involve a stabilizer foot havingtwo or more multiple link support members. The stabilizer foot istypically positioned as desired at the surgical site with at least onesupport member connecting the stabilizer foot to a stable support.Subsequently, one or more additional support members may be provided andconnected to the stabilizer foot, typically at different locations, toobtain optimum stabilization.

One aspect of the present invention involves an apparatus forstabilizing a coronary artery on a patient's heart comprising astabilizer foot adapted to engage the surface of the heart, a firstsupport member, and a second support member. The first support membermay have a distal end connected to the stabilizer foot at a first distalarticulating joint and a proximal end connected to a stable support at afirst proximal articulating joint. The second support member preferablyhas a distal end connected to a second distal articulating joint and aproximal end connected to a stable support at a second proximalarticulating joint. The present invention may involve third and, ifdesired, fourth support members each having separate distal and proximalattachments. Having more than one support member connecting to thestabilizer foot and the stable support at different locations providesgreatly improved stabilization.

The stabilizer foot may be configured to have a variety of differentdistal articulating joints including pinned or rotational joints, balljoints, malleable joints, or the like. In a preferred embodiment, thefirst or second distal articulating joint is a ball and socket joint,typically formed between a ball or ball-shaped member extending from thestabilizer foot and a mating cavity formed within the most distal linkof the first or second support member. The first and second distalarticulating joint may also be a rotational joint, typically formedbetween a generally cylindrical post extending from the stabilizer footand a mating cylindrical surface provided within the most distal linksof the first or second support member. Preferably, the first distalarticulating links is a ball and socket joint allowing optimumpositioning of the stabilizer foot against the beating heart and thesecond distal articulating links is a simple rotational joint thatfacilitates quick attachment of the second support member to thestabilizer foot.

Preferably, the first support member includes a distal link, a proximallink, and a plurality of interconnecting links therebetween. Each of theinterconnecting links preferably has a ball or ball-shaped end and asocket or socket-shaped end. The ball shaped ends of the interconnectinglinks are cooperatively engaged with the socket shaped ends of adjacentinterconnecting links thereby forming articulating ball joints betweenadjacent interconnecting links in a manner that allows the first supportmember to articulate to varied positions, shapes, or orientations alongits length.

Each of the interconnecting links preferably has a central hole throughwhich a flexible wire or cable may be routed. The cable has a distal endconnected to the distal link and is routed through the central hole ofeach of the interconnecting links, preferably exiting through theproximal link. Applying a tensile force to the proximal end of the cablefrictionally locks the articulating ball joints between adjacentinterconnecting links, thereby causing the support member to becomerelatively rigid.

The resulting force distribution amongst the multiple support membersallows the support members to be configured with relatively smallcross-sectional profiles even when the lengths of the support membersare quite long. For example, the first support member preferably has alength of greater than about 6.5 inches and an average diameter of lessthan about 0.5 inches. More preferably, the first support member has alength of about 7.0 inches to about 9.0 inches. The smaller profiles andlonger lengths advantageously provide the surgeon with greater visualand instrument access to the surgical site.

The stabilizer foot itself may be adapted to engage the surface of theheart using negative pressure, for example, by way of a vacuum chamberor by way of a plurality of vacuum ports. More preferably, thestabilizer foot has at least one contact surface, preferably textured orotherwise adapted to frictionally engage the surface of the heart. In apreferred embodiment, the stabilizer foot has a first contact surfaceand a second contact surface, the second contact surface being spacedapart from and oriented substantially parallel to the first contactsurface.

Typically, the first and second contact surfaces will be positioned onopposite sides of the target coronary artery. The stabilizer foot mayhave first and second posts extending about the first and second contactsurfaces to which third and fourth support members may be connected. Thethird and fourth support members have proximal ends connected to thestable support at third and fourth proximal articulating joints,respectively. Preferably, the stable support is a sternal or ribretractor but may be any other stable structure.

Another aspect of the present invention involves an apparatus forstabilizing a coronary artery on a patient's heart which includes aretractor, a mount base operably connected to the retractor, a mountbody connected to the mount base at a first articulating joint along afirst axis, a multiple link support member, and a stabilizer foot. Theproximal end of the support member is preferably operably connected tothe mount body along a second axis. The stabilizer foot may be operablyconnected to the distal end of the support member and adapted to engagethe surface of the heart, for example, using friction or negativepressure.

In a preferred embodiment, the first axis is at an angle relative to thesecond axis, the angle being between about 120 degrees and about 45degrees, more preferably the angle being about 90 degrees. This dualaxis articulation allows optimum access and positioning of thestabilizer foot and support member within the surgical field.

The retractor preferably has opposing retractor blades adapted to engageopposite sides of an access incision. In a preferred embodiment, atleast one of the retractor blades further comprises a rail. Preferably,the rail has first and second rail tabs extending therefrom along thelength of the rail. Preferably, the mount base is adapted to engage theretractor blade at any desired position along the rail. In a preferredembodiment, the mount base has first and second channels sized to engagethe rail tabs. The second channel may be moveable relative to the firstchannel such that the first and second channels slidably engage the railtabs when the second channel is in a first position and the channelsfrictionally grip the rail tabs when the second channel is in a secondposition.

In a preferred embodiment, the multiple link support member comprises adistal link a proximal link and a plurality of interconnecting linkstherebetween. Each of the interconnecting links may have a ball orball-shaped end and a socket-shaped end, the ball-shaped ends beingcooperatively engaged with the socket-shaped ends of adjacentinterconnecting links thereby forming articulating ball joints betweeninterconnecting links. The distal link preferably has a mating cavityadapted to receive a ball-shaped member extending from the stabilizerfoot.

Another aspect of the present invention involves an apparatus forstabilizing the coronary artery which involves a stabilizer foot adaptedto engage the surface of the beating heart and a multiple links supportmember having a proximal end link, a distal end link, and a plurality ofcenter links arranged end-to-end therebetween. The support memberpreferably has a cable extending through the center links. In apreferred embodiment the distal end link comprises a first member and asecond member, the second member having at least first and secondportions defining a cavity therebetween for receiving the ball-shapedmember. The first member may have a bearing surface adapted to engage atleast a portion of the second member to urge the first and secondflexible portions together against the ball-shaped member.

The first member preferably has a bore adapted to receive at least aportion of the second member. The distal end of the cable is attached tothe second member such that when the second member is pulled in adirection towards the first member by operation of the cable, the firstand second flexible portions are engaged by the bearing surface causingthem to frictionally engage the ball-shaped member with sufficient forcethe position of the stabilizer foot relative to the distal end link. Inone embodiment, the bearing surface is frustoconical.

The proximal end of the support member is preferably attached to astable support, which in a preferred embodiment comprises a retractorhaving opposing retractor blades for engaging opposite sides of anaccess incision. The stabilizing apparatus may further include a mountbase operably connected to the retractor and a mount body connected tothe mount base at a first articulating joint along a first axis. Theproximal end link is preferably connected to the mount body along asecond axis. The first axis may be angled relative to the second axis,the angle being between about 120 degrees and about 45 degrees.

Another aspect of the present invention involves a method forstabilizing a coronary artery on a patient's heart which may comprisethe steps of creating an access opening into the patient's thoraciccavity to gain access to the beating heart, providing a stabilizerdevice having a stabilizer foot operably connected to a support memberhaving a flexible condition and a relatively rigid condition, with thesupport member in a flexible condition, positioning the stabilizer footto engage the surface of the heart adjacent the coronary artery, causingthe support member to assume the relatively rigid condition to therebyresist movement of the stabilizer foot, providing at least oneadditional support member, attaching the distal end(s) of the additionalsupport member(s) to the stabilizer foot, and causing the additionalsupport member(s) to assume a relatively rigid condition to therebyprovide additional resistance against movement of the stabilizer foot.The access opening is preferably created using a retractor and themethod may further include the step of attaching the support member andthe additional support member(s) to the retractor.

These and other features of the present invention will become more fullyapparent from the following description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a tissue stabilizer system constructedaccording to the principles of the present invention.

FIG. 2 is a perspective view illustrating the stabilizer foot of thetissue stabilizer system of FIG. 1.

FIG. 3 is top plan view illustrating the distal connector of the tissuestabilizer system of FIG. 1.

FIG. 4 is a perspective view a tissue stabilizer system constructedaccording to the principles of the present invention.

FIG. 5 is a perspective view of a tissue stabilizer system of FIG. 4illustrating the attachment of additional support members.

FIG. 6 is an exploded perspective view illustrating the details of themount assembly of the tissue stabilizer system of FIGS. 4 and 5.

FIG. 7 is a cross-sectional view illustrating a distal ball and socketattachment to a stabilizer foot.

FIG. 8 is a perspective view illustrating a tissue stabilizer systemconstructed according to the principles of the present invention.

FIG. 9 is a cross-sectional view of a portion of the tissue stabilizersystem of FIG. 8.

FIG. 10 is a cross-sectional view illustrating one embodiment of adistal connection of a support member to a stabilizer foot.

FIGS. 11 and 12 are perspective views illustrating preferred embodimentsof the housing and clamp members, respectively, of the distal connectionof FIG. 10.

FIG. 13 is a cross-sectional view illustrating a preferred distalconnection to a stabilizer foot.

FIG. 14 is an exploded perspective view illustrating the distalconnection of FIG. 13.

FIG. 15 is a cross-sectional view illustrating an alternative distalconnection of a support member to a stabilizer foot.

FIG. 16 is a perspective view illustrating one of the distal linkcomponents of the distal connection of FIG. 15.

FIG. 17 is a front plan view illustrating the distal connection of FIG.15 in an articulated relative to the support member.

DETAILED DESCRIPTION

The present invention involves surgical instruments for accessing andstabilizing tissue during a surgical operation and methods for theiruse. The device described herein may be used in a wide variety ofsurgical applications that require a tissue structure to be stabilizedor immobilized to provide a substantially stable and motionless targetsurgical field on which a surgical procedure can be performed. By way ofexample only, the preferred embodiments described in detail below aredirected to the stabilization of a portion of the heart to facilitate asurgical procedure on or within the heart, such as a coronary arterybypass graft procedure.

Although the devices and methods of the present invention may haveapplication in both conventional stopped-heart procedures and beatingheart procedures, they are preferably used to stabilize the beatingheart during a CABG operation which has been specially developed tofacilitate completion of an anastomosis, typically between a targetcoronary artery and a bypass graft or source artery, without requiringcardiac arrest and cardiopulmonary bypass.

A typical beating heart CABG procedure involves accessing the beatingheart by way of a sternotomy, mini-sternotomy, thoracotomy,mini-thoracotomy, or other suitable access incision, positioning atissue stabilizer on, around, or adjacent a coronary artery to stabilizethe coronary artery, creating an arteriotomy in the coronary artery, andanastomosing the bypass graft or source artery to the arteriotomy.Typically, the tissue stabilizer has a foot member or heart engagingmember at one end for engaging the surface of the beating heartgenerally using friction, negative pressure, or both. The stabilizer isconnected at the other end to a stationary object such as a sternalretractor, rib retractor, or other such stationary structure. Exemplardevices and methods for accessing the beating heart and mounting astabilizer device are disclosed in U.S. Pat. No. 6,331,158, the entiretyof which is herein incorporated by reference.

The devices and methods of the present invention involve tissuestabilizers which are constructed to provide superior maneuverabilityand improved tissue stabilization at a target site, for example on thebeating heart. The present invention may involve stabilization devicesthat use at least one multiple link support member to operably connect astabilizer foot to a stable support, such as a retractor. To minimizemotion at the stabilizer foot and improve the overall stabilization of atarget site, the present invention may involve a stabilizer foot havingtwo or more multiple link support members.

When the stabilizer system is configured to use more than one supportmember, at least one of the support members may be pre-attached to thestabilizer foot. After the stabilizer foot has been positioned at thetarget site to be stabilized, the pre-attached support member may belocked in place according to its particular construction to effectuate asignificant measure of stabilization or immobilization of the targetsite. One or more additional support members may then be introduced tothe target site, attached to the stabilizer foot, and locked in place tofurther minimize motion of the tissue at the target site. Although thismethod of stabilizing a tissue structure will be described in detailbelow with regard to multiple link support members, it is equally wellsuited for use with continuous rigid or malleable support members, or acombination of the various types of support members.

To improve the ability of a support member to be easily articulated fromits attachment at the stable support to the stabilizer foot positionedat a target site, one or more of the multiple link support members maybe operably associated with an attachment or mount which providesadditional degrees of freedom at its connection to the stable support.For example, the mount may provide a rotational joint or ball joint atthe connection to the stable support so that the proximal link or linksof the multiple link support member can be more freely oriented towardsthe target site, even before any articulation of the links provided bythe support member. This tends to result in less visual and instrumentobstruction of the surgical site by the support member and allows thestabilizer foot to be positioned at a target site using a support memberconstructed with fewer links.

A typical construction of the multiple link support members utilizes aseries of in-line ball and socket links, each having a significantlylimited range of motion. To provide a greater range of motion foradjusting the orientation of the stabilizer foot relative to the supportmember, the present invention may involve a distal connection to thestabilizer foot which allows a greater range of articulation. Theability to articulate the stabilizer foot through an extended range ofmotion greatly increases the ability of the device to be satisfactorilypositioned at target sites which are remote, angled, or otherwisedifficult to reach.

Referring to the figures wherein like numerals indicate like elements,an exemplar tissue stabilization system using multiple support membersis illustrated with respect to FIGS. 1-3. Tissue stabilization system100 is shown in place over a coronary artery on the surface of a heartin FIG. 1. Tissue stabilization system 100 generally includes a heartengaging member or stabilizer foot adapted to engage the surface of theheart and one or more support members connecting the foot to a stablesupport, such as for example retractor 102. Preferably, the stabilizerfoot is connected to the stable support using a plurality of multiplelink support members. The heart engaging member or stabilizer foot mayis preferably configured to atraumatically engage the surface of theheart using mechanical friction, negative pressure, or a combination ofthe two and may be of any suitable construction.

In a preferred embodiment, stabilizer foot 125 is connected to retractorassembly 102 using multiple link support members 110 and 112. Supportmembers 110 and 112 are preferably a series of interconnecting ball andsocket links having a common tension wire or cable (not shown) extendingtherethrough which may be tensioned to axially compress the ball andsockets together to frictionally lock the individual joints betweenlinks. Thus, the position and orientation of support members 110 and 112may be relatively freely articulated until the cable is tensioned tofrictionally engage the individual joints, making the support memberrelatively stiff or rigid.

In one embodiment, support members 110 and 112 have a proximal housing115 at which the proximal end of the tension cable may be operablycoupled to knob 116. Although not visible in the view shown, knob 116typically has a threaded portion for engaging a threaded coupling on theproximal end of the tension cable such that rotation of knob 116relative to housing 115 tensions the cable and compresses the linksalong support members 110 and 112. Of course, the cable may be tensionedusing any other suitable mechanism that can be actuated easily by theuser in the context of a surgical setting.

Stabilizer foot 125 preferably has one or more support members which arepre-attached to stabilizer foot 125, and one or more releasable supportmembers which can be connected to stabilizer foot 125 after stabilizerfoot 125 has been positioned as desired on 20 the surface of the heart.In a preferred embodiment stabilizer foot 125 has two support members112 pre-attached at distal ball joint 130, preferably at raised base126. When stabilizer foot 125 is configured to use two pre-attachedsupport members 112 as shown, the distal ball joints 130 are generallyspaced apart a predetermined distance along raised base 126.

If stabilizer foot 125 is configured to use only one pre-attachedsupport member, it may be attached to either one of the two distal balljoints as may be clinically advantageous, or a single center ball jointmay be provided. In addition, a single support member may be providedwhich bifurcates to connect to any two of the provided ball joints asdesired. Such a bifurcated support member provides the desirablemultiple point mounting at the stabilizer foot with minimal obstructionof the surgical field.

Distal ball joint 130 may be any suitable articulating joint that allowsstabilizer foot 125 to be positioned over a target artery as shown andthen locked with the support member as tension cable becomes taught. Ina preferred embodiment, stabilizer foot 125 may have one or moregenerally upward extending posts 132 each supporting a ball orball-shaped member 134 which may be engaged by the distal end of supportmembers 112. In one embodiment, ball shaped member 134 may beconveniently engaged by way of a support member having a distal collettype construction as illustrated in FIG. 7, discussed in detail below.

With support members 112 attached to stabilizer foot 125 in anarticulating fashion at distal ball joints 130, stabilizer foot may beplaced over the target site as desired. In the case of stabilizing acoronary artery on the beating heart for performing a CABG procedure,stabilizer foot 125 preferably has first and second contact members 127and 128 which may be placed on opposite sides of a target coronaryartery to allow the application of the required stabilization forces tothe surrounding or adjacent tissue without significant compression orocclusion of the coronary artery. Once the stabilizer foot has beenpositioned at the target site, one or both of support members 112 isstiffened or locked using knob 116, thereby providing a significantmeasure of stabilization to the affected tissue.

In some instances, it may be possible for a single multiple link supportmember to provide acceptable stabilization. In many cases, however, andespecially cases involving the difficult access requirements of multiplevessel bypass procedures on the beating heart, a single multiple linksupport member cannot achieve sufficient rigidity for optimumstabilization without resorting to excessive forces, disadvantageouslyshort support member lengths, or excessively large support memberprofiles or diameters. Further, depending on the final articulatedposition of a particular multiple-link support member, the supportmember may be better able to resist forces delivered along certainvectors and somewhat less able to resist (i.e., more flexible) forcesdelivered along other vectors relative to the support member. As aresult, having more than one support member attaching at differentglobal relationships to the encountered forces tends to significantlyincrease the ability of stabilizer foot 125 to resist movement whichwould otherwise occur as a result of the forces delivered by thecontacted tissue.

If the stabilization provided by support members 112 alone issufficient, the surgical procedure can proceed without furtheralteration or adjustment of the stabilization system. To furtherminimize or eliminate motion of stabilizer foot 125 one or morereleasable support members 110 may be attached to the front ofstabilizer foot 125 using any convenient attachment means. Supportmembers 110 may be attached to a ball and post arrangement similar tothat of support member 112. In another embodiment, support members 110may have distal connectors 135 which attach to posts 129 preferablyextending generally upwardly from contact members 127 and 128.

Preferably, distal connector 135 is constructed to clamp onto post 129to prevent any relative motion therebetween. Distal connector 135 mayhave clamp portion 136 connected to link portion 150. Link portion 150has a socket adapted to receive a ball portion of the distal link ofsupport member 110 and a generally centered counterbore in which thedistal end of the tension cable which forces the multiple links intofrictional engagement may terminate. Clamp portion 136 has a center bore138 sized to fit over pin 129 and a slot 140 generally separating clampportion 136 into first clamp half 142 and second clamp half 144. Athreaded extension of knob 156 may be assembled through clearance hole146 and threaded into threaded hole 148. Tightening knob 156 then forcesfirst and second clamp halves 142 and 144 together, thus fixing distalconnector 135 relative to post 129. Once connected to support member125, support members 110 may be locked using knobs 116, preferablyacting on a central tension cable (not shown).

The pre-attached support members 112 and the releasable support members110 are preferably oriented in such a manner as to minimize visual andinstrument access to the surgical site. To provide greater flexibilityin positioning the support members in a desirable fashion, one or moreof the housings 115 may be mounted to the stable support using anarticulating joint which provides one or more additional degrees offreedom about which housing 115 may be articulated. In one embodiment,housings 115 have a generally cylindrical bore adapted to rotate aboutmating pins 120 which are fixedly connected to the stable support, inthis case retractor assembly 102.

The retractor assembly can be any suitable retractor suitable to createthe desired access opening for operating on the heart, or other tissuestructure of interest. In a preferred embodiment, retractor assembly 102has opposing retractor arms 106 and 108 which may be driven apart by asuitable toothed or cable drive actuated by handle 104. Each ofretractor arms 106 and 108 have a means for attaching support members110 and 112, which in the embodiment shown comprise posts 120 which maybe rotationally received by cylindrical mating bores in housings 115. Inthis manner, each of housings 115 and support members 110 and 112provided may be rotated about posts 120 to obtain nearly any desiredorientation. Housings 115 are fixed in place relative to posts 120 bytightening their respective knobs 118 which are threaded into housings115 to bear against posts 120.

In a preferred method of operating tissue stabilization system 100,opposing retractor arms 106 and 108 are first placed within a suitableincision and actuated to create an access opening through which thebeating heart may be directly viewed. Stabilizer foot 125, with supportmembers 112 connected thereto, is positioned over a target site,preferably with contact members 127 and 128 on opposite sides of acoronary artery targeted which is to be anastomosed to a source or graftbypass vessel. With stabilizer foot 125 roughly in position, knobs 118associated with housings 115 of support members 112 are tightened toprevent further relative motion at post 120. If desired, a suitablecompressive force may be manually applied to stabilizer foot 125 usingthe operator's hand, the support members themselves, or other suitableinstrument. Support members 112 may then be locked by actuation ofassociated knobs 116 to provide a measure of stabilization to the hearttissue and coronary artery.

If further stabilization is desired, one or both of support members 110may be attached proximally to retractor arms 106 or 108. The distalconnectors 135 may then be placed over posts 129 and secured using knobs156. Respective housings 115 of support members 110 may be locked inplace relative to posts 120 using associated knobs 118. Any desiredfinal adjustments may be made to the position or orientation of supportmembers 110, and then support members 110 are locked or made rigid byactuating knob 116. With the site stabilized, an arteriotomy 101 is thencreated in the target coronary artery and the graft or source vessel isanastomosed to the substantially motionless arteriotomy 101.

Using more than one support member and connecting each to a separatelocation on the stabilizer foot has a number of advantages. The multiplepoint mount as just described provides superior stabilization even withsupport members that are constructed to have a relatively small outerdiameter and are constructed to operate using somewhat less force in thecentral tension cable. In essence, the multiple support member systemallows the use of smaller profile or lower force support members thanwould normally be required to stabilize a tissue structure such as thebeating heart.

The multiple support member system also allows one or more of thesupport members to be configured to have a longer length than wouldnormally be feasible in single support member systems due to theresulting inability to stabilize attributable to such longer lengths.The long length advantageously allows the body of the support member tobe articulated to a position which will not inhibit access to thesurgical site, yet still facilitates placement of the stabilizer foot atlocations remote from the proximal attachment to the stable support.

The benefits of increased length are even greater when the supportmember has also been constructed to take advantage a smaller outerdiameter. For example, even with support members having a length of 6.5inches or more the diameters of the individual links may remain quitesmall, preferably the largest diameter being 0.5 inches or less, morepreferably in the range of about 0.250 inches to about 0.50 inches. In apreferred embodiment, the support members are constructed to have apredetermined length in the range of about 7 inches to about 8.5 inchesand an average diameter in the range of about 0.375 inches to about 0.5inches. Again, the capability to adequately stabilize using supportmembers having long lengths and small outer diameters greatly improvesthe ability of the surgeon to arrange the surgical site for optimumvisual and instrument access.

Another tissue stabilization system capable of utilizing more than onesupport member is illustrated in FIGS. 4-7. Stabilization system 200generally includes a stable support in the form of a sternal retractor212 having opposing blades 214 and 216 for creating an access opening, astabilizer foot for engaging the tissue to be stabilized, and one ormore multiple link support members connecting the stabilizer foot to thesternal retractor. Preferably, the support members have proximal mountsthat can be moved to any desired position along the length retractorblades. The proximal mounts may also be provided with increased degreesof freedom to allow for optimum adjustment and positioning of thesupport members and stabilizer foot.

The stabilizer foot can be any type of foot or end member adapted toengage the surface of the heart using, for example, mechanicalcompression and friction, negative pressure, or any combination of thetwo. Preferably, the stabilizer foot is adapted to frictionally engageand press against the surface of the heart. In a preferred embodiment,stabilizer foot 225 has first and second contact members 227 and 228connected by raised base portion 226 which is preferably in the form ofa re-curve. An underside region of contact members 227 and 228preferably has a textured region specifically configured to frictionallyengage the surface of the heart.

Stabilizer foot 225 preferably has at least one multiple link supportmember which preferably has a series of articulating elements or linksinterconnected together with a tension cable extending throughpassageways provided in each element or link. In a first state, themultiple links are allowed to freely articulate thus rendering thesupport member quite flexible, bendable or positionable. In a secondstate, the support member may be made relatively stiff or rigid byapplication of an appropriate tension applied to the cable to force themultiple links into frictional engagement with each other. In apreferred embodiment the links are joined together by articulating balland socket joints.

In a preferred embodiment, stabilizer foot 225 has at least one supportmember which may be pre-attached to stabilizer foot 225 to facilitatethe placement of stabilizer foot 225 within the surgical site and toprovide at least initial stabilization of the tissue at the targetedsite. Support member 210 preferably has an interconnecting series ofball and socket links 290, each having a generally spherically-shapedsocket 292 on one end and a generally ball-shaped member 291 on theother end, the ball-shaped members of one link adapted to engage withinthe socket of the next link.

Support member 210 connects proximally to a stable support preferably byway of an instrument mount or the like which provides one or moredegrees of freedom which are not in line with the proximal links ofsupport member 210. In a preferred embodiment, support member 210connects proximally to instrument mount assembly 220. Preferably,instrument mount assembly 220 has ball joint 205 about which at least aportion of instrument mount assembly 220 can be articulated to achieve adesirable position and orientation of the proximal end portion ofsupport member 210. Preferably, ball joint 205 has a working axis whichis at an angle with respect to the working axis of the ball and socketjoints of the proximal links of support member 210. The angle istypically between about 120 degrees and about 45 degrees and ispreferably about 90 degrees.

In a preferred embodiment, retractor blades 214 and 216 have top rails260 upon which instrument mount assembly 220 may be mounted. Top rails260 preferably have tabs 268 and 269 along the length of rails 260 whichmay be engaged by hook or channel features or the like provided oninstrument mount assembly 220. This allows instrument mount assembly 220to be positioned at any desirable location along the length of rails260.

Mount assembly 220 is shown in more detail in FIG. 6. Preferably,instrument mount assembly 220 has a fixed rail grip 253 and a moveablerail grip 254 for engaging tabs 268 and 269. Rail grips 253 is part ofmount base 245 and moveable rail grip 254 is part of articulating hingemember 256, which is pivotally attached to mount base 245 by way ofhinge pins 247, or other suitable fastener. Mount base 245 is free tocontrollably slide along rail 260 to any desired position at which pointhinge member 256 and rail grip 254 may be articulated in a clampingmanner towards rail grip 253 on mount base 245 effectively clampingmount base 245 onto rail 260. Rail grips 253 and 254 are preferably inthe form of C-shaped channels sized to receive rail tabs 268 and 269.

Hinge member 256 may be articulated using any suitable mechanism capableof pivoting hinge member 256 to a closed position and holding it there.In a preferred embodiment, hinge member 256 is articulated by action ofcam 258. Cam 258 has a bore 257 which cooperatively rotates about camguide 261 on mount base 245. Base lever 262 may be used to rotate cam258 about cam guide 261. Additional details and variations of the cam,rail grips and the connection between mount base 245 and rails 260 canbe found in U.S. Pat. No. 6,331,158 which has already been incorporatedby reference above.

Ball joint 205 is generally created between ball 255 provided at the topof mount base 245 and a socket or mating cavity 259 within mount body250. Preferably, ball 255 and mating cavity 259 are preferablyspherical. Base post 265 extends vertically upward through bore 246 ofmount base 245 and vertical bore 252 of mount body 250 until enlargedend portion 263 becomes biased against mount base 245. Top mount knob202 may then be threaded onto threaded shaft 267 whereby mount base 245and mount body 250, with ball 255 received within mating cavity 259,becomes captured between top mount knob 202 and enlarged end portion263. Continued tightening of top mount knob 202 over threaded shaft 267forces ball 255 harder against mount body 250 until the friction betweenmating surfaces on ball 255 and mating cavity 259 become so great as toeffectively resist any relative movement, thus locking ball joint 205.

As mentioned above a flexible tension wire or cable is preferably routedthrough the links of support member 210 for the purpose of urging theassociated ball and socket joints into frictional engagement renderingsupport member 210 relatively rigid. In a preferred embodiment, cable295 passes through each of the links forming support member 210 and theninto mount body 250, through transverse bore 266 in base post 265, andterminating at threaded connector 275 which is preferably swaged orotherwise fixedly connected to cable 295. Threaded connector 275 may beengaged by internal threads 207 provided in knob 204. Knob 204 ispreferably rotatable relative to mount body 250, and may preferably havea guide housing 206 which is received within a mating bore (not visiblein this view) in mount body 250.

With knob 204 engaged against mount body 250, rotation of knob 204causes internal threads 207 to operate on threaded connector 275 tocause cable 295 to be pulled or released depending on which directionknob 204 was rotated. Threaded connector 275 preferably has an endhousing 276 which is keyed against rotation within mount body 250, thuscausing the desired linear translation of threaded connector 275required to tension cable 295. Keying threaded connector 275 againstrotation ensures that rotation of knob 204 will result in the desiredrelative movement between internal threads 207 and threaded connector275 instead of allowing threaded connector 275 to merely rotate andtorsionally wind up cable 295. In a preferred embodiment, end housing276 is provided with one or more protrusions or keys 277 which mate withkeyways (not shown) within mount body 250.

Mount body 250 may engage the proximal most link of support member 210using any type of convenient fixed, rotational or ball and socketconnection. In a preferred embodiment, mount body 250 has a horizontalbore 251 and proximal link 280 of support member 110 has housing 281which is adapted to rotationally mate with bore 251. Bore 251 andhousing 281 may be tapered somewhat so that they more readilyfrictionally lock as cable 295 is tensioned to compress links 290 aswell as proximal link 280 into mount body 250. Proximal link 280preferably has ball on its distal end which forms a ball and socketjoint as it mates with link 290.

Support member 110 is preferably connected distally to stabilizer foot225 in any convenient manner which allows stabilizer foot 225 to bearticulated as required for the surgical procedure contemplated. In oneexample, stabilizer foot 225 may simply have a socket for receiving ball291 of the distal most link of support member 110 and cable 295 attachesto and pulls against stabilizer foot 225 to compress the multiple linksalong support member 110. Articulation of stabilizer foot 225 is thenlimited to the range of motion provided by that type of ball and socketjoint.

Referring to FIG. 7, the distal end of support member 110 is preferablyadapted to receive and secure a ball member extending from raised base226 of stabilizer foot 225 forming a distal ball joint 230. Preferably,raised base 226 has ball 322 extending from post 324. Post 324 may haveconnecting base 326 to facilitate attachment to raised base 226, forexample by welding or by mechanical fasteners or other suitableinstrumentality. The distal end of support member 110 preferably hasdistal member 310 with a socket 315 adapted to mate with ball 322.Because ball 322 and mating socket 315 of distal member 310 are notburdened by having a cable passing through, they may be considerablysmaller in size and have an extended range of motion. By also includingone or more distal slots 318 leading into the spherical socket sized toaccommodate post 324, the range of motion of the stabilizer foot 225 maybe further increased. Preferably, distal member 310 has four slots 318spaced roughly at 90 degree intervals.

In a preferred embodiment, distal member 310 has multiple sections orportions which are constructed to operate in the manner of a collet tolock the position of ball 322 within spherical cavity 315. Preferably,distal member 310 has one or more, preferably two to four, slots 316extending a distance up the side of distal member 310, forming first andsecond flexible distal member portions 313 and 314. Slots 316 arepreferably configured to provide sufficient flexibility in the structureof distal member 310 to allow distal member portion 313 and distalmember portion 314 to flex towards each other, thus causing sphericalcavity 315 to collapse around ball 322.

The distal member portions may be urged together in any convenientmanner. For example, causing distal member portions 313 and 314 tocollapse and lock onto ball 322 may be accomplished by providing collarmember 300 just proximal to distal member 310 against which distalmember 310 may be urged by operation of cable 295 to force the distalmember portions together. In a preferred embodiment, collar member 300has a proximal spherical socket 302 for receiving ball 291 from link 290of support member 110 and a central bore 305 for receiving distal member310. Central bore 305 preferably has an angled or conical bearingsurface 303 which mates with a mating angled or conical surface 312provided on distal member 310. Mating surface 312 extends to a diameterwhich is greater than the extents of conical surface 303 such thatdistal member portions 313 and 314 are forced together as mating surface312 is drawn within conical surface 303.

Distal member 310 is preferably drawn into collar 300 by pulling cable295 proximally in relation to mount body 250 using knob 204 as describedabove. Cable 295 is preferably routed through openings 293 providedthrough each link 290, through opening 304 of collar 300, and attachingdistally to distal end member 310. In a preferred embodiment, cable 295has a cable end member 306 installed through opening 308 in distal endmember 310. Cable end member 306 may have flange 307 having a diametergreater than that of opening 308 so that the distal end of cable 295 canpull on distal member 310 with sufficient tension to lock not onlydistal member 310 onto ball 322 but each of the ball and socket jointsalong support member 110.

Preferably, distal member portions 313 and 314 spring open far enough inthe relaxed state to allow spherical cavity 315 to easily fit over ball322. This allows the associated support member to be attached to ball322 and removed from ball 322 as desired. For example, the supportmember may be detached from ball 322, the stabilizer foot repositioned,and then reattached to ball 322. Also, when a CABG procedure is beingperformed endoscopically, for example, through small access openings orports, the stabilizer foot can be positioned onto the heart through afirst port or access incision, and one or more additional supportmembers can be inserted through one or more additional access incisionsand connected to the stabilizer foot to provide improved stabilization.

In a preferred embodiment of the present invention, support member 210operates to connect stabilizer foot 225 to instrument mount assembly 220which may be positioned and fixedly attached to a stable support, suchas sternal retractor 212. Sternal retractor 212 may be of any suitableretractor construction as is known in the art, but preferably is of theconstruction described in U.S. Pat. No. 6,331,158 which has already beenincorporated by reference above. Preferably, sternal retractor 212comprises first and second retractor blades 214 and 216 which areconnected to a suitable drive for controllably spreading 214 and 216apart in a generally parallel fashion.

First and second retractor blades 214 and 216 preferably each have atleast one channel or sternal engaging member 218 adapted to engageopposite sides of an access incision. Sternal engaging member ispreferably U-shaped, curved, or otherwise shaped for securely engagingthe incised sternum in a manner that allows very little movement ofretractor blades 214 and 216 relative to the incised sternum. As firstand second retractor blades 214 and 216 are forced apart, engagingmembers 218 are correspondingly force the incision open to providedirect access to the desired surgical site. In the example of a sternalapproach to the heart, engaging members 218 are adapted to engage eachside of the incised sternum to reliably hold and engage the sternum asit is forced open to expose the thoracic cavity and ultimately theheart.

A preferred drive for spreading apart first and second retractor blades214 and 216 generally includes bar 215 having housing 221 fixed thereto,moveable housing 222 and handle assembly 224 which facilitates movementof moveable housing 222 relative to bar 215. First blade 214 and secondblade 216 are preferably operably attached to moveable housing 222 andfixed housing 221, respectively. First and second retractor blades 214and 216 may be permanently attached or may be removably attached.Retractor blades 214 and 216 may be attached in any suitable fashionincluding, for example, threaded connections or other mating features onthe retractor blades or housings themselves, ordinary or specializedmechanical fasteners, and cam or latching mechanisms adapted to securethe platform blades to the housings. In a preferred embodiment, bothmoveable housing 222 and fixed housing 221 are constructed with featureswhich engage, secure, and support first and second retractor blades 214and 216 in an operable position, thus providing a retractor assembly 212which is ready for surgical use.

Bar 215 preferably includes a number of teeth 213 evenly spaced along atleast a portion of its length. Handle assembly 224 preferably includes ameans for engaging teeth 213 so as to drive moveable housing 222relative to bar 215 to any desired position under load where it remainsso positioned against the load without need for any applied input orholding force. The means for engaging teeth 213 may be any suitablegear, ratchet, cog or like mechanism. Preferably, handle assembly 224drives moveable housing 222 using one or more drive pins which maysuccessively engage teeth 213 in a cogging manner has handle 229 isrotated by the user.

Platform blades preferably incorporate a number of additional featureswhich enhance the performance of the retractor system such as recessed,locking suture channels 270, flexible tissue retainers 285 and rails 260to which instrument mount assembly 220 or the like can be mounted. Thesefeatures are described in further detail in U.S. Pat. No. 6,331,158which has already been incorporated by reference above.

Tissue stabilization system 200 provides a convenient system with whichto position and secure stabilizer foot 225 in a desired position andorientation for stabilizing a tissue structure such as a target coronaryartery on the surface of the heart. Rails 260 provided on first andsecond retractor blades 214 and 216 allow as many instrument mounts,each having multiple link support members for attachment to stabilizerfoot 225, as may be necessary to be added and positioned along rail 260.

In use, support member 210 is typically pre-attached to stabilizer foot225 at distal ball joint 230. Referring again to FIGS. 4 and 5,instrument mount assembly 220 is preferably assembled over rail 60 andpositioned to a desired location along rail 60 and locked into place.Stabilizer foot 225 is brought to or near the surgical site and thecoronary artery that is to be stabilized. Ball joint 205 may then belocked in place using top mount knob 202. Stabilizer foot 225 may befurther adjusted or oriented relative to the surface of the heart asdesired. Support member 210 and distal ball joint 230 are thenpreferably locked in place using knob 204, thus providing a measure ofstabilization to the surgical site.

If the stabilization provided by support member 210 alone is sufficient,arteriotomy 101 may be created to begin the standard anastomosisprocedure. However, in a preferred embodiment, stabilizer foot 225 isprovided with one or more additional post supported ball members towhich additional support members, either of the continuous or multiplelink type, may be added to provide additional stabilization. In apreferred embodiment, balls 232 and 234 are provided on stabilizer foot225 near the unsupported end of each of contact members 227 and 228. Ifadditional stabilization is desired, instrument mount assembly 235having multiple link support member 238 can be brought attached tostabilizer foot 225 at ball 232 to form distal ball joint 239 andsecured in place using top mount knob 236 and knob 237.

Even further stabilization can be provided, if desired, by attachinginstrument mount assembly 240 having multiple link support member 243 torail 260 as shown and attaching the distal end of support member 243 toball 234 to form distal ball joint 244. Support member 243 may besecured in place using top mount knob 240 and knob 242. In oneembodiment, stabilization system 200 will have at least one supportmember attached to rails 260 of both retractor blades 214 and 216.Alternatively, all the support members may be mounted only a single railor either of retractor blades 214 and 216.

Instrument mount assemblies 235 and 240 are preferably constructed inthe same manner as instrument mount assembly 220 described above. Eachof the instrument mount assemblies have a ball joint which is notin-line with the cable 295 and the proximal links of the respectivesupport members. This allows the proximal end of each support member tobe articulated, oriented, or otherwise directed about the working axisof the ball joint. The ability of the instrument mount to articulate inthis fashion allows the stabilizer foot to be more easily placed at awider range of target surgical sites and greatly alleviates problemsassociated with the limited range of motion associated with the linksfrom which typical multiple link support members are constructed.

In addition, the additional degrees of freedom provided by theinstrument mount assemblies may allow the support members to haveconstructions which allow improved rigidity or smaller overall size. Theball and socket joints formed by the links of multiple link supportmembers must have sufficient contact area to support the loads requiredto generate the locking frictional forces. In general, to obtain agreater range of motion in support members having ball and socket jointsof a particular diameter, the contact area must typically be decreaseddue to larger holes through the ball and socket links to accommodate theincreased cable travel and due to the smaller degree of engagementbetween the mating ball and sockets required to gain the increasedmotion. The articulation provided by the instrument mount assembly mayallow at least a portion of the support members to satisfactorilyoperate with a reduced range of motion, thus allowing a constructionhaving greater contact area or smaller overall size.

The articulation of instrument mount assemblies 220, 235, and 240 may belocked independently by operation of top mount knobs 202, 236, and 241respectively. In many instances, it may be preferred by the surgeon tohave the capability to lock ball joint 205 at a desired position leavingsupport member 210 free to articulate for positioning stabilizer foot225 relative to the tissue structure to be stabilized. Further, fineadjustment to the position of stabilizer foot 210 during a surgicalprocedure may preferably be accomplished by loosening any of knobs 204,237, or 242 to allow articulation of the respective support memberwithout disturbing the position of the instrument mount.

In other instances, primarily determined by surgeon preference, it maybe desirable to tighten all the degrees of freedom using only a singleknob, lever, etc. Referring to FIGS. 8 and 9, tissue stabilizer assembly400 illustrates an instrument mount assembly which allows the variousarticulating joints provided at stabilizer foot 325, along supportmember 480, and within instrument mount assembly itself to be lockedusing a single user interface, such as knob 414. Preferably, theinstrument mount assembly allows support member 480 to be operablyconnected to a stable support, such as a retractor or the like, throughan articulating joint that is not in line with the links of supportmember 480.

The instrument mount assembly preferably has a ball joint between mountbase 421 and mount body 422 along a first axis 482 and provides for theconnection of the proximal end of support member 480 generally alongaxis 481. Axis 481 and 482 may be at any convenient angle to each other,typically less than about 120 degrees, more preferably between about 100degrees and about 45 degrees, and are most preferably generallyperpendicular to each other. The ability to lock the articulating jointsalong the different axis using a single knob tends to reduce theoperational complexity of the instrument while maintaining the abilityto easily maneuver and secure the stabilizer foot through an accessincision and into contact with a tissue structure to be stabilized.

In a preferred embodiment, the articulating joint between mount base 421and mount body 422 is preferably a ball and socket configuration whichmay be created between generally spherical ball 429 provided at the topof mount base 421 and a mating cavity or socket 440 within mount body422 adapted to receive at least a portion of ball 429. Preferably, theball and socket configuration may also include a generally spherical end432 on base post 430 which couples with mating surface 447 in theinterior of mount base 421.

Base post 430 is generally positioned through mount base 421 such thatspherical end 432 abuts mating surface 447 within mount base 421. Inthis configuration, mount base 421 is controlled between spherical end432 and socket 440 and becomes locked in place as the distance betweenspherical end 432 and socket 440 is reduced to a dimension which clampsthat portion of mount base 421 residing therebetween. Preferably, basepost 430 has an extension or support post 436 which is engaged within areceiving hole in the top of mount body 422 to facilitate the desiredcontrolled motion relative to mount body 422.

Support member 480 preferably has a number of ball and socket elementsor links 290 and tension cable 486 extending through passages providedin each link. In a preferred embodiment, the proximal most of links 290is connected to mount body 422 by way of proximal connecting link 475which, on a distal end has ball 478 which is engaged within a socket onmating link 290.

Connecting link 475 preferably engages mount body 422 in a manner whichallows connecting link 475 to be frictionally locked against mount body422 as cable 486 is tensioned. The interface between mount body 422 andconnecting link 475 may be any suitable connection including arotational joint or a ball and socket joint. In a preferred embodiment,mount body 422 has a frustoconical surface 423 which mates withfrustoconical surface 424 on connecting link 475 to form a rotationaljoint between mount body 422 and connecting link 475.

The tension in cable 486 may be manually increased or decreased byrotating knob 414 in the appropriate direction. In a preferredembodiment, the proximal end of cable 486 is connected to a pull pin450. Preferably, the proximal end of cable 486 is positioned withinhollow region 456 and secured using a suitable squeezing, crimping,swaging or like process. Pull pin 450 has a threaded section 453 whichis engaged by internal threads 418 of knob 414. When the internalthreads 418 of knob 414 are advanced along threaded section 453 of pullpin 450 by rotation of knob 414 in the appropriate direction, pull pin450 and thus cable 486 is pulled in a direction generally opposite tothe direction indicated by arrow 483. Urging pull pin in this directionrelative to mount body 422 causes the articulating joints along cable486, including those associated with connecting link 475, to compressand become relatively rigid as the frictional forces reach sufficientmagnitude. To prevent pull pin 450 from excessively rotating as knob 414is rotated, pull pin 450 may be keyed against rotation relative to mountbody 422.

At the same time knob 414 is operating to lock support member 480, knob414 may also be used to drive base post 430 upwards in the directionindicated by arrow 484 to lock the position of mount body 422 relativeto mount base 421 as described above. In a preferred embodiment, basepost 430 has a lifting or cam surface 435 which may be used to close theposition of base post 430 relative to mount body 422 so as to lock theposition of mount body 422 relative to mount base 421. Cam surface 435may be urged upwards along axis 482 by urging a suitable thrust surfacein the direction indicated by arrow 483 to engage and lift cam surface435. The thrust surface is generally associated with knob 414 such thatadvancement or translation of knob 414 along threaded section 453 ofpull pin 450 causes cam surface 435 to move up or down in relation tothe position of the mating surface.

The thrust surface may be integral with guide housing 416 of knob 414 oron a separate element which is engaged by knob 414. In a preferredembodiment, cam surface 435 is urged upwards by operation of lifter 465which slides over pull pin 450, preferably over a non-threaded or smoothsection of pull pin 450. Lifter 465 may have a contoured, shaped,radiused, or chamfered thrust surface 466 configured to mate with camsurface 435.

Guide housing 416 of knob 414 is preferably sized to fit within matingguide bore 415 of mount body 422. As knob 414 is tightened, and internalthreaded portion 418 is urged along threaded section 453 of pull pin450, guide housing 416 pushes lifter 465 in the direction indicated byarrow 483, thus engaging cam surface 435 with mating surface 466 causingbase post 430 to move upwardly towards mount body 422 and socket 440 inthe direction indicated by arrow 484. As with the other articulatingjoints, tightening knob 414 proportionally increases the frictionalforces at the socket 440 ball 429 and spherical end 432/mating surface447 interfaces until they become functionally locked against relativemotion. Compression spring 460 may be provided to pre-load the mechanismso that a minimum amount of frictional forces can be more easilymaintained.

The instrument mount assembly of tissue stabilizer assembly 400 may besecured to any suitable stable support and is preferably constructed tocooperatively attach to a sternal or rib retractor having a railstructure as described above with reference to FIGS. 4 and 5. In apreferred embodiment, hinge member 412 having rail grip 472 is pivotallymounted to base 421 by way of pins or the like at hinge mount 462. Cammember 445 may be rotated about cam guide 438 using base lever 410causing hinge member 412 to urge rail grip 472 towards rail grip 471 onmount base 421, thus facilitating instrument mount 400 to be secured toa rail or other suitable structural component.

A stabilizer foot adapted to engage the surface of the beating heart,preferably using negative pressure, friction, or both, may be connectedto the distal end of support member 480 in any manner which provides thenecessary degrees of freedom and range of motion to allow the stabilizerfoot to be positioned as required by the contemplated procedure. In oneembodiment, a stabilizer foot having a ball member associated therewithmay be releasably attached to support member 480 in the manner describedabove with reference to FIG. 7.

Another distal connection for operably connecting a stabilizer foothaving a ball member to a support member is illustrated in FIGS. 10-12.Stabilizer foot 225 preferably has ball 365 extending from post 366which is in turn securely attached to raised base portion 226. Distalconnection 375 preferably allows free rotation of stabilizer foot 225when in an unlocked state and effectively inhibits or prevents motionbetween ball 365 and distal connection 375 when in a locked state.

In a preferred embodiment, distal connection 375 includes housing 350,which has a spherical shaped cavity or socket 354 for receiving a matingball shaped portion of the last ball and socket link of support member480, and a clamp member 355 moveably disposed relative to housing 350.Ball 365 is disposed within a cavity or bore 359 within the distal endof clamp member 355 and is engaged by a narrowed portion 352 which maybe one or more protrusions or surfaces that are angled, frustoconical,spherical, or like shaped to securely engage a portion of the bottomhalf of ball 365. The upper portion of ball 365 abuts a portion ofhousing 350, or a component fixed relative to housing 350, such thatrelative movement of clamp member 355 in a first direction tends to urgeball 365 against the abutting portion or component of housing 350 tofrictionally lock ball 365 between narrowed portion 352 of clamp member355 and housing 350.

In a preferred embodiment, housing 350 has a main body 351 having mainbore 353 extending therethrough. Main bore 353 is sized and configuredto slidingly receive body 356 of clamp member 355. Main bore 353 andbody 356 are preferably generally cylindrical, although other shapes andconfigurations which allow clamp member 355 to controllably sliderelative to housing 350 are suitable.

The abutting portion or fixed component of housing 350 into which ball365 is urged by operation of clamp member 355 may be of any suitableextension of housing 350 or other configuration that provides thenecessary support to allow the ball to become frictionally locked inplace. In a preferred embodiment, clamp member 355 has a central passageor bore 359 into which compression column 374 may be disposed. Thedistal end 373 of compression column 374 is adapted to frictionallyengage a portion of the top half of ball 365 and preferably has aconcave shape that is generally conical or spherical. The distal end 373may optionally include a textured, rubberized, or like portion toenhance friction and thus improve locking.

Movement of compression column 374 relative to housing 350 may belimited or eliminated by way of locking pin 370 which is preferablysecured within transverse mating holes 372 of housing 350 by anysuitable technique including mechanical threads, adhesives, welding,heat staking, or interference fit. Locking pin 370 passes throughpassageways or holes 357 which are sufficiently oversized relative tothe pin to allow clamp member 355 to translate relative to housing 350without interference from locking pin 370.

Ball 365 may be positionally locked between clamp member 355 andcompression column 374 by urging clamp member 355 towards compressioncolumn 374 in any convenient manner. Preferably, a distal end of cableor wire 360 is attached to clamp member 355 which may be tensioned tolock ball 365. Cable 360 is preferably routed through a plurality ofball and socket links which make up all or a portion of a support memberas described above. When cable 360 is tensioned, both ball 365 and thelinks of the support member become frictionally locked against furtherrelative movement. Cable or wire 360 may be preferably attached to clampmember 355 using a crimping process or other suitable technique orfastener. Cable 360 may include an enlarged or collar portion 362 whichmay be crimped into place within central bore 359 of clamp member 355.

In some instances, acceptable maneuverability may be achieved with adistal connection having only a rotational degree of freedom at theconnection to the stabilizer foot and relying on the degrees of freedomprovided by links 290 of support member 480. In a preferred embodimentillustrated in FIGS. 13 and 14, stabilizer foot 325 is provided withpivot boss 495. Pivot boss 495 preferably has a generally cylindricalouter surface about which stabilizer foot 325 may pivot when mated withcooperating cylindrical pivot surface 488 on distal link 485. Distallink 485 has spherical socket 489 adapted to mate with the ball end oflink 290 of support member 480. Pivot boss 495 may be connected to baseportion 226 of stabilizer foot 325 by way or a post member, rib, or web496 connected to and extending from base portion 226.

The distal end of cable 486 is preferably connected to stabilizer foot325 in a manner which will not cause the cable to bend or bindexcessively as pivot boss 495 of stabilizer foot 325 rotates withinmating surface 488 of link 485. In a preferred embodiment, the distalend of cable 486 is routed through central passage or hole 487 andconnected to stabilizer foot 325 using end connector 490 having a cableconnecting portion 491 which facilitates a crimped or swaged connectionto cable 486. End connector 490 may fit within an interrupted portion orslot 493 to rotate about pin 497 through hole 492. Pin 497 may befixedly secured within holes 498 within pivot boss 495.

This connection allows stabilizer foot 325 to be rotationallyarticulated about pivot boss 495 over a wide range of motion. Additionalarticulation of stabilizer foot 325 is limited to those degrees offreedom and range of motion provided by the ball and socket jointsformed along the multiple links of support member 480. If desired, oneor more additional degrees of freedom may be provided having an extendedrange of motion over the basic ball and socket joints provided by links290 of support member 480. FIGS. 15-17 illustrate a distal connection toa stabilizer foot which provides an additional degree of rotationalfreedom over the single rotational joint of the prior embodiment.

The distal connection is shown in cross-section in FIG. 15. Stabilizerfoot 535 again has pivot boss 495 having at least one cylindrical outersurface for rotating with a cooperating mating surface and aninterruption or slot in which end connector 490 may be secured in themanner described above, preferably to a raised base portion 536. In apreferred embodiment, pivot boss 495 is connected to link 290 of supportmember 480 by way of first and second distal links 505 and 515.Preferably, pivot boss 495 and second distal link 515 are cooperativelyengaged to provide a first rotational degree of freedom about a firstaxis and second distal link 515 and first distal link 505 arecooperatively engage to form a second rotational degree of freedom abouta second axis. The first and second axes are preferably substantiallyperpendicular, but could be at any desired angle depending on thearticulation desired for stabilizer foot 535 relative to support member480.

A preferred second distal link is illustrated in FIG. 16. Second distallink 515 has a cylindrical pivot surface 518 adapted to receive pivotboss 495, forming a rotational joint about axis 526 as indicated byarrow 528. Second distal link 515 also has an arcuate upper profile 516which is preferably adapted to engage mating arcuate channel 509 offirst distal link 505. Arcuate channel 509 is adapted to slide alongarcuate profile 516 generally about axis 527 as indicated by arrow 529.Second distal link 509 preferably has sides 522 which may be securelycaptured within arcuate channel 509. The configuration of second distallink 515 provides sufficient contact area for secure frictionalengagement yet has a relatively thin width which does not impingeoutward towards the surgical working area above first and second contactmembers 537 and 538.

Cable 486 is routed through openings 293 of multiple links 290, throughcentral opening 508 of first distal link 505, through second distal link515 and rotatably secured at the center of pivot boss 495 using a pin orthe like. Second distal link has a slot or channel 520 to provideclearance for cable 486 as first distal link 505 is articulated relativeto second distal link 515. An articulate position of first distal link505 relative to second distal link 515 is illustrated in FIG. 17. Aswith the previous embodiments, each of the articulating joints alongcable 486 may be frictionally locked by applying an appropriate tensionto cable 486.

Regardless of the particular configuration of the stabilizer foot andthe distal connection used to secure the stabilizer foot to the supportmember 480, the method of using the tissue stabilizer assembly 400 isessentially the same. An access opening is created to provide access tothe tissue structure to be stabilized. Preferably, the access opening iscreated through the sternum using a sternal retractor having opposingblades, at least one or which having a rail member, such as rail 60.

Next, tissue stabilizer assembly 400 may be brought to engage rail 60.Rail grips 471 and 472 of tissue stabilizer assembly 400 are positionedto loosely engage rail 60. Tissue stabilizer assembly 400 may betraversed along rail 60 to a desired position, where rail grips 471 and472 may be caused to frictionally lock or grip rail 60, preferably byrotating hinge member 412 using cam member 445.

Stabilizer foot 325 may be positioned at the target site, preferablywith contact members 227 and 228 on each side of a target coronaryartery on the surface of the beating heart. To optimize access to thesurgical site, the position of support member 480 may be adjusted ifdesired by articulating links 290 or by articulation mount body 422relative to mount base 421. Stabilizer foot 325 may then be manuallyengaged with the surface of the heart as desired to effectuate thedesired stabilization. This may involve manually applying a desiredamount of manual compression or, if the stabilizer foot so constructed,it may involve engaging the surface of the heart using negativepressure, adhesive tape, or other suitable instrumentality.

With the stabilizer foot in place and engaged as desired, knob 414 maybe rotated in the appropriate direction to mechanically or frictionallylock both the in-line articulating joints provided along cable 486 aswell as the articulating joint or joints provided between mount body 422and the stable support, in this case retractor rail 60. If the surgicalsite is sufficiently stabilized, the surgical procedure can beperformed.

For greater stabilization, stabilizer foot 325 may optionally haveadditional connections for securing additional support members, such asposts 129 as described with reference to stabilizer foot 125 or balls232 and 234 as described above with reference to stabilizer foot 225. Inthat case, one or more additional support members, preferably havingmount assemblies adapted to be secured to rail 260, may be furtherattached to the stabilizer foot, adjusted as necessary and locked inplace to further minimize motion at the target surgical site.

While certain embodiments are illustrated in the drawings and describedherein, it will be apparent to those skilled in the art that manymodifications can be made to the embodiments without departing from theinventive concepts herein described. For purposes of illustration only,the principles of the present invention has been primarily describedwith reference to stabilizing a beating heart during a coronary arterybypass procedure but may readily be applied to other types surgicalprocedures not specifically described. Many other uses are well-known inthe art, and the concepts described herein are equally applicable tothose other uses. Further, it is contemplated that the differentcomponents of the various exemplar embodiments described above can becombined to achieve any desirable construction. Accordingly, theinvention is not to be restricted except by the claims which follow.

1-32. (canceled)
 33. An apparatus for stabilizing a portion of apatient's heart comprising: a stabilizer foot adapted to engage thesurface of the heart, the stabilizer foot having a proximal portion anda distal portion; a first support member having a distal end connectableto the stabilizer foot at a first articulating joint located on theproximal portion of the stabilizer foot, and a proximal end connectableto a stable support; and a second joint located on the stabilizer footdistally to the first articulating joint, the second joint is capable ofreceiving a second member.
 34. The apparatus of claim 33 wherein thestable support is a retractor.
 35. The apparatus of claim 33 wherein thesecond articulating joint is different than the first articulatingjoint.
 36. The apparatus of claim 33, further comprising a second memberhaving a distal end connectable to the second articulating joint. 37.The apparatus of claim 36, wherein the second member further comprises aproximal end connectable to the stable support.
 38. The apparatus ofclaim 33 wherein the stabilizer foot has at least one textured contactsurface adapted to frictionally engage the surface of the heart.
 39. Theapparatus of claim 33 wherein the stabilizer foot has a first contactsurface and second contact surface, the second contact surface beingspaced apart from and oriented substantially parallel to the firstcontact surface.
 40. The apparatus of claim 39, wherein the first andsecond contact surfaces extend distally from the proximal portion of thestabilizer foot.
 41. The apparatus of claim 40, wherein the secondarticulated joint of the stabilizer foot is located dorsally to thefirst contact surface.
 42. The apparatus of claim 41, further comprisinga third articulating joint, wherein the third articulating joint islocated dorsally to the second contact surface.
 43. The apparatus ofclaim 33 wherein the stabilizer foot is adapted to engage the surface ofthe heart using negative pressure.
 44. The apparatus of claim 33,wherein the second joint is an articulating joint.
 45. A method forstabilizing a portion of a patient's heart with a stabilizer devicehaving a stabilizer foot operably connected to a support member, thesupport member having a flexible condition and a relatively rigidcondition; the stabilizer foot having a proximal joint and a distaljoint located distal to the proximal joint, the method comprising thesteps of: creating an access opening into the thoracic cavity;positioning the stabilizer foot to engage the surface of the heartadjacent a coronary artery; causing the support member to assume therelatively rigid condition to thereby resist movement of the stabilizerfoot; and securing a distal end of an additional member to the distaljoint on the stabilizer foot.
 46. The method of claim 45, furthercomprising: securing the support member to a stable support, andsecuring the additional member to the stable support.
 47. The method ofclaim 46, wherein the stable support is a retractor configured forcoronary artery bypass grafting procedures.